I have several systems which have the OS installed in a language I
don't understand. When I try to run the OUI I get it in that language
and even though I've performed a few dozen installations and could
probably do it in my sleep by now, I do need to make sure I'm not
installing the wrong thing.

It's even more complicated when it's an eastern language (japanese).

In unix systems I basically solve this with and environment variable
(NLS_LANG, NLS_LANGUAGE, NLS_TERRITORY for those of you who wonder)
but I have found no similar solution for windows systems.